The present invention relates to a semiconductor light emitting device, for example, a semiconductor laser, and a method of fabricating the same.
In a semiconductor light emitting device, for example, a semiconductor laser, it is desired that a light emitting end surface of the device, that is, an end surface of an optical resonator, is composed of an optical mirror surface. In general, such an end surface of an optical resonator is formed of a cleavage crystal plane. In the case where an end surface of an optical resonator is formed of a cleavage crystal plane, generally, a semiconductor substrate is first prepared in which a plurality of stripe-like resonators each being equivalent to several semiconductor light emitting devices are formed in parallel to each other. Then, the semiconductor substrate is cleaved along planes crossing the lengthwise direction of the stripe-like optical resonators into a plurality of semiconductor bars each having a width corresponding to a length of a resonator of a semiconductor laser chip to be finally obtained, wherein the cleavage surface is taken as the end surface of the resonator of the semiconductor device finally obtained. A protective film or an optical film having a specific reflectance is formed on each side surface of the semiconductor bar, wherein end side surface constitutes an end surface of the resonator. Then, the semiconductor bar is cut along lines between respective stripes to form semiconductor laser chips.
The above method, however, has a problem that since the worker must handle a plurality of semiconductor bars after one semiconductor substrate is divided into multiple semiconductor bars, the handling thereof is laborious, resulting in degraded productivity on a large scale.
On the other hand, a method in which an end surface of a resonator is formed via an etched surface has been proposed. This method does not require additional work for forming end surfaces of resonators by the above cleavage, that is, additional work for preparing semiconductor bars. As a result, according to this method, the worker can handle a semiconductor substrate equivalent to several semiconductor lasers as it is substantially up to the sizing step for forming semiconductor laser chips, to thereby increase productivity on a large scale.
In the method using etching, however, there occurs a problem that the etched surface is not necessarily smooth and accordingly, in a semiconductor laser finally obtained, a so-called "facet degradation" is increased, to thus reduce luminous efficiency and lower service life.